SKIN TREATMENT DEVICE COMPRISING A PULSE MODULATOR

Abstract

The invention relates to a device for the cosmetic treatment of keratin materials with the aid of an electric current, comprising at least one generator (1) which produces an elementary signal formed by a high-frequency signal which is amplitude-modulated by a medium-frequency signal and at least one electrode (5) connected to an output of the generator (1) and which can be moved over a body area to be treated and a counterelectrode (6), the generator (1) comprising an elementary signal processing unit comprising a pulse modulator (4) which delivers a low pulse-frequency current wave.

Claims

1: Device for the cosmetic treatment of keratin materials with the aid of an electric current, comprising at least one generator which produces an elementary signal formed by a high-frequency signal which is amplitude-modulated by a medium-frequency signal and at least one electrode connected to an output of the generator and which can be moved over a body area to be treated and a counterelectrode, wherein the generator comprises an elementary signal processing unit comprising a pulse modulator which delivers a low pulse-frequency current wave.

2: The device according to claim 1, wherein the pulse modulator is a pulse width modulator PWM or a pulse amplitude modulator PAM.

3: The device according to claim 1, wherein the pulse modulator has a switching frequency of between 1 Hz and 100 Hz.

4: The device according to claim 1, wherein the pulse modulator is a PWM modulator delivering a signal U(t) defining a duty cycle of between 1% and 75%.

5: The device according to claim 1, wherein the pulse modulator delivers a low-frequency modulation having a sinusoidal, triangular, square or rectangular form.

6: The device according to claim 1, wherein the pulse modulator delivers a signal U(t) having a pulse duration of between 4 ms and 8 ms.

7: The device according to claim 1, wherein a microcontroller generates the pulse modulator and a voltage regulator capable of adjusting a maximum voltage of the current wave as a function of an impedance measured between the electrode and the body area.

8: The device according to claim 1, wherein the high-frequency signal has a frequency of between 1 MHz and 100 MHz, preferably between 1 MHz and 10 MHz and more preferentially between 3 MHz and 5 MHz.

9: The device according to claim 1, wherein the medium-frequency signal has a frequency of between 1 kHz and 1000 kHz, preferably between 10 kHz and 700 kHz and more preferentially between 300 kHz and 500 kHz.

10: The device according to claim 1, wherein the generator comprises a DC-CDI (capacitive discharge ignition) circuit run at high frequency and receiving as input a medium-frequency voltage.

11: The device according to claim 1, wherein it comprises a source of heat, light, for setting the application end piece in motion, notably a sonic, ultrasonic or iontophoretic vibration.

12: The device according to claim 1, wherein it comprises a resistive or capacitive sensor for controlling a movement, a temperature, an impedance or a pH.

13: The device according to claim 1, wherein it comprises a cosmetic product reservoir.

14: The device according to claim 1, wherein it is an electrostimulatory device.

15: Cosmetic process, wherein it comprises the use of a device according to claim 1.

Description

PREFERRED EMBODIMENTS

[0080] Preferably, the device according to the invention has one or more of the following features, on their own or in combination: [0081] the pulse modulator has a switching frequency of between 1 Hz and 100 Hz. This frequency is adapted to produce a particularly efficient signal. [0082] the pulse modulator is a PWM modulator delivering a signal U(t) defining a duty cycle of between 1% and 75%. With this duty cycle, the signal intensity is satisfactory. [0083] the pulse modulator delivers a low-frequency modulation having a sinusoidal, triangular, square or rectangular form. These forms are ideal for obtaining a suitable elementary signal. [0084] the pulse modulator delivers a signal U(t) having a pulse duration of between 4 ms and 8 ms. Thus, the user does not perceive the momentary absence of current on his skin. [0085] a microcontroller generates the pulse modulator and a voltage regulator capable of adjusting a maximum voltage of the current wave as a function of an impedance measured between the electrode and the body area. The circuit is easy to produce and compact. [0086] the high-frequency signal has a frequency of between 1 MHz and 100 MHz, preferably between 1 MHz and 10 MHz and more preferentially between 3 MHz and 5 MHz. [0087] the medium-frequency signal has a frequency of between 1 kHz and 1000 kHz, preferably between 10 kHz and 700 kHz and more preferentially between 300 kHz and 500 kHz. [0088] the generator comprises a DC-CDI (capacitive discharge ignition) circuit run at high frequency and receiving as input a medium-frequency voltage. The device is produced with components that are available on the market and readily accessible. [0089] the device comprises a source of heat, light, for setting the application end piece in motion, notably a sonic, ultrasonic or electroporation vibration. The treatment may be improved and, what is more, more efficient. [0090] the device comprises a resistive or capacitive sensor for controlling a movement, a temperature, an impedance or a pH. The safety of the device is increased.

DESCRIPTION OF THE FIGURES

[0091] The invention will be better understood on reading the following detailed description of non-limiting illustrative embodiments of the invention and on examining the appended, schematic and partial drawing, in which:

[0092] The invention is not limited to the examples illustrated. In particular, the features of the various exemplary embodiments which have just been described can be combined with each other.

[0093] FIG. 6 shows an example of an elementary signal U(t) in damped sinusoidal form.

[0094] FIGS. 7 and 8 show examples of pulse frequency waves.

[0095] FIG. 9 shows an exemplary embodiment of a circuit according to the invention.

[0096] FIG. 6 shows a symmetrical damped sinusoidal signal of high frequency equal, for example, to 3 MHz.

[0097] It is amplitude-modulated by a medium-frequency signal, for example of 358 kHz, 620 kHz, 720 kHz.

[0098] FIG. 7 is a 100 Hz sinusoidal current wave with a peak voltage of 630 V obtained as the output from a pulse modulator.

[0099] FIG. 8 is a 100 Hz sinusoidal current wave with a peak voltage from 50 V to 340 V obtained as the output from a pulse modulator.

[0100] The signals generated by a skin treatment appliance give improved treatment efficiency and less tingling and heating on the treated area.

[0101] FIG. 9 shows a generator 1 comprising a DC-CDI circuit 2 receiving as input an alternating voltage U.sub.0 at a frequency of medium frequency F.sub.m, for example 1000 kHz. This alternating voltage may be taken from the current distribution network, for example via a step-down transformer located outside the generator 1. Moreover, an oscillator 3 of high frequency F.sub.h, for example 3 MHz, may be connected to the control input of the DC-CDI circuit 2. The result of this is that the output signal from the DC-CDI circuit 2 is a high-frequency signal F.sub.h (3 MHz) which is amplitude-modulated by the medium-frequency signal F.sub.m(1000 kHz) known as the elementary signal. The high-frequency oscillations, of 3 MHz in this instance, change in amplitude inside a medium-frequency envelope (1000 kHz), for example like the signal shown in FIG. 6.

[0102] The elementary signal is applied to a pulse modulator 4, one output terminal of which is connected to an electrode 5, for example a metal electrode, whereas the other output terminal is connected to a counterelectrode 6 intended to come into contact with the person and serving as earth. The electrode 5, for its part, will be moved slowly over the area of the epidermis to be treated. The signal available at the output of the pulse modulator 4 is a low pulse-frequency current wave, for example like that shown in FIG. 7 or 8.